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World J Methodol. Sep 20, 2022; 12(5): 402-413
Published online Sep 20, 2022. doi: 10.5662/wjm.v12.i5.402
Table 1 Causes of elevated thyrotropin levels
Transient increase in TSH
Permanent increase in TSH
Non-thyroidal illnessAssay interference
Thyroiditis TSH hormone resistance
Medications: Amiodarone and Lithium Adrenal insufficiency
Lack of adherence to treatment Obesity
Table 2 Guideline recommendations for treatment of subclinical hypothyroidism
Degree of subclinical hypothyroidism
ATA 2012[36]
ETA 2013[37]
NICE 2019[38]
TSH > 10 mIU/LLevothyroxine should be considered. (Grade B)Younger patients (< 65 to 70 yr): Treatment with levothyroxine is recommended, even in the absence of symptoms. (Grade 2); Older patients (> 70 yr): Treatment with levothyroxine should be considered if clear symptoms of hypothyroidism are present or if the risk of vascular events is high. (Not a graded recommendation, but part of the treatment algorithm)All adults (on 2 occasions, 3 mo apart) consider treatment.
TSH: ULN to 10 mIU/LTreatment should be considered on the basis of individual factors (i.e., symptoms suggestive of hypothyroidism, a positive test for antibodies to thyroid peroxidase, or evidence of atherosclerotic cardiovascular disease, heart failure, or associated risk factors for these diseases). (Grade B, because of a lack of randomized, controlled trials)Younger patients (< 65 to 70 yr): A trial period of treatment with levothyroxine should be considered when symptoms suggestive of hypothyroidism are present. (Grade 2); Older patients (especially > 80 to 85 yr): Careful follow-up with a wait-and-see strategy, generally avoiding hormonal treatment, is recommended. (Grade 3)Age < 65 years (on 2 occasions, 3 mo apart): Consider a 6-mo trial of levothyroxine if symptoms are present.
Table 3 Criteria for prediabetes

WHO[39]
ADA[40]
FPG (mg/dL)110-125100-125
2-h plasma glucose (mg/dL)140-199140-199
HbA1c (%)5.7-6.4
Table 4 Criteria for defining osteopenia
Category
Definition
Treatment recommendation
“Moderate risk”, Endocrine Society guidelines 2019[74]Clinical: No prior hip or spine fractures, BMD T-score at the hip and spine both above -2.5, 10-yr hip fracture risk < 3% or risk of major osteoporotic fractures < 20%Reassess fracture risk in 2-4 yr. Country-specific guidelines for treatment
ISBMR guidelines 2021[75]BMD T-score between -1.0 and -2.5 at the femoral neck or lumbar spine, 10-yr probability of a hip fracture ≥ 3.5%, or a 10-yr probability of a major osteoporosis-related fracture ≥ 10.5% based on the FRAX tool (based on limited data in Indians)Advisable to initiate treatment
Table 5 Clinical spectrum of preclinical conditions: Looking at hard facts

Prediabetes
Subclinical hypothyroidism
Osteopenia
MACS
Clinical diseaseDiabetesOvert primary hypothyroidismOsteoporosisCushing’s syndrome
Prevalence of preclinical condition5.5%-53.1%[43], IFG -6.2%[41], IGT -10.6%[41]4.3%-15%[20]54%-80%[65]5%-48%[6]
Prevalence of clinical condition10.5%[41]0.2%-5.3%[19]2%-26.3%[64]0.3% of patients with adrenal incidentalomas[5]
Dx criteriaFPG: 100-125, 2-h PPG: 140-199, HbA1C: 5.7-6.4Elevated TSH level with a fT4 level that is within the population specific rangeT-score between -1 to -2.5Abnormal 1-mg dexamethasone suppression test with absent stigmata of Cushing’s disease.
Progression5%-18.3%[54,55,60] 2%-6%[22]16% risk of major osteoporotic fracture in 10 years[67]< 1%[13]
Regression/reversal19%[54]60%[21]Stays static or progresses2%-44%[6,11]
Long-term sequelaeMicrovascular and macrovascular complications of diabetes, Cardiovascular risk Markers of cardiovascular function (such as left ventricular diastolic function) and lipid profile deteriorate with subclinical hypothyroidismFractures Hypertension, Diabetes, Dyslipidemia, Osteoporosis
Short-term consequencesFatigue, muscle weakness, cold intolerance
Preventive optionsLifestyle and behavioural therapy, drugsLifestyle and behavioural therapy, drugsLifestyle and behavioural therapy, drugsLifestyle and behavioural therapy, drugs, surgery
PharmacotherapyMetformin L-thyroxine Calcium and vitamin DMifepristone, metyrapone
Surgery---Adrenalectomy
True preventionxxxx
Adverse effects of treatments availableB12 deficiency Bone loss, cardiac arrhythmias in elderlyOvertreatment can predispose to hypervitaminosis DHypocortisolism
Recommendations/GuidelinesMetformin should be considered in those with BMI ≥ 35 kg/m2, those aged < 60 yr, and women with prior gestational diabetes mellitus with IGTTSH > 10 mIU/L, consider treatment; TSH < 10 mIU/L, consider treatment if symptoms suggestive of hypothyroidism, positive antibodies to thyroid peroxidase, or evidence of atherosclerotic cardiovascular disease, heart failure, or risk factors for these diseasesCountry-specific guidelines for treatmentIndividualized approach to consider patients with ‘autonomous cortisol secretion’ due to a benign adrenal adenoma and comorbidities potentially related to cortisol excess for adrenal surgery
Grade of recommendationLevel of evidence A[58]Grade B, BEL 1 (Best evidence rating level)[36]-(⊕OOO) Very low level of evidence/recommendation[3]